The present invention relates to an operating means with a seal, for a timepiece, according to the introductory part of claim 1. For sealing operating organs of a timepiece usually O-rings are applied. Since these do not always seal the inside of the timepiece to a satisfactory degree, already for some time there has been undertaken a variety of efforts to develop seals with improved sealing properties, in that the cross sectional shape of the O-rings has been dropped.
From CH 562 468 a dust-tight crown for timepiecees is known, which comprises an elastically deformable sealing packing with an S-shaped bent cross sectional shape. Although this sealing packing in comparison to O-rings on the side of the inner space is formed out differently than on the side which faces the surroundings, this packing acts roughly equally in both directions, i.e. that on excess pressure in the timepiece inner space it has a similar sealing behaviour as with a excess pressure in the surroundings.
On the one hand a packing of such a shaping ensures that a formation of a considerable excess pressure in the inside of the timepiece cannot occur since it comprises a tapering packing part which in such a situation comes away from the wall of the bore.
If however the pressure of the surroundings of a timepiece equipped with such a crown increases, for example on diving, then this packing likewise only puts up a small resistance to the penetration of matter into the inside of the timepiece on account of the shaping of the mentioned packing part.
Furthermore this solution has the disadvantage that on placing back the winding axis, from the hand setting position into the basic position, particles of dirt from the tapering packing part may be co-transported into the inside of the timepiece. By way of the contamination of the sealing region the danger of penetration of water is also considerably larger.
Furthermore such a crown requires an exact length setting and assembly of the winding-up shaft.
With CH 453 221 there is shown an operating organ with an L-shaped seal which comprises a conical sealing surface which is in contact with the outer walling of a sleeve arranged in the timepiece housing. This sleeve is formed conically so that the placing of the crown onto the sleeve can be carried out simply. In the placed-on condition the sealing is deformed so far that the conical sealing surface blends into a cylindrical one and accordingly bears on the sleeve over the whole circumference with a close fit, and with a relatively large pretensioning. For the purpose of an additional increasing of the bearing force the sealing is designed in a manner such that it broadens towards the inside in the direction to the axis.
As a rule the solution implies a differing sealing behaviour in both directions, however it has the effect that it only prevents penetration of matter into the inside of the timepiece in a limited manner and that a rapid reduction of excess pressure in the timepiece is not possible.
According to CH 324 259 between a bore in the crown and the outer walling of the sleeve there is arranged a sealing ring with a V-shaped cross section in whose wedge-shaped annular groove there is arranged a metal ring which is axially impinged by a spring. By way of the spring pressure the two arms of the V-shaped sealing ring are radially expanded in order to produce a bearing force on the one hand with respect to the sleeve and on the other hand to the bore of the crown.
Also with this solution there may arise a considerable excess pressure on the inside of the timepiece.
Furthermore CH 304 789 shows sealing disks which in each case bear on an annulus-shaped surface in a deformed manner and under pretension.
Although with this solution a reduction in excess pressure in the timepiece is possible, narrow limits are set to the axial path of the winding-up shaft.
Moreover also an exact length setting of the winding-up shaft is required.